System and method for quantitative measurements of a material's complex permittivity with use of near-field microwave probes

A method for measurement of a material's complex permittivity, comprising the step of:

• positioning a near-field microwave probe at a predetermined distance d* from a first standard sample having a dielectric constant ∈r1;
• measuring a relative resonant frequency shift δf1=(fe−f1)/fe of said near-field microwave probe for said first standard sample;
• positioning said near-field microwave probe said predetermined distance d* from at least one second standard sample having a dielectric constant ∈r2;
• measuring a relative resonant frequency shift δf2=(fe−f2)/fe of said near-field microwave probe for said at least one second standard sample, wherein f1 and f2 are the resonant frequencies of said probe positioned said distance d* from said first and said at least one second standard samples, respectively, and fe is the resonator frequency of said probe for an empty resonator;
• calculating geometrical coefficients A and B using said measured relative resonant frequencies δf1 and δf2 and dielectric constants ∈r1 and ∈r2 for said first and at least one second standard samples;
• positioning and maintaining said near-field microwave probe said distance d* from a sample under study;
• measuring a relative resonant frequency shift δfs=(fe−fs)/fe of said near-field microwave probe for said sample under study;
• measuring a change in the quality factor Δ(1/Q) of said near-field microwave probe for the resonator loaded with said sample under study and for an empty resonator;
• calculating the dielectric constant of said sample under study using said resonant frequency shift δfs and said geometrical coefficients A and B;
• and
• calculating the dielectric loss tangent (tan δ) of said sample under study using said Δ(1/Q) and said geometrical coefficients A and B.